The EIP9 Protein Interacts With WUS Protein And Regulates The Stem Cells In Shoot Apical Meristem Of Arabidopsis

The growth and development of higher plants is mainly dependent on the division and differentiation of meristem,among which,Shoot Apical Meristem(SAM)determines the formation of some organs on the ground,such as stems,leaves and flowers.WUS(WUSCHXEL)is a crucial regulator in the stem cell of SAM,which can induce stem cells and inhibit their differentiation to maintians the homeostasis of stem cells.WUS-CLY feedback regulation loop is an important pathway to regulate the dynamic balance between proliferation and differentiation of stem cells,and plays a key role in maintaining the cell and structural stability of SAM.EIP9 protein belongs to the family III of molecular partner DnaJ/Hsp40,which is widely expressed in various tissues and organs of Arabidopsis thaliana,especially in the apical meristem,throughout the whole plant growth process.Subcellular localization examination showed that EIP9 is mainly located in the nucleus and cytoplasm.The interaction between EIP9 protein and WUS protein was proved by yeast double hybridization and pull-down experiment,respectively.Furthermore,genetic experiments demonstrated that EIP9 has important roles in the growth and development of plant shoot apical meristem,vascular bundle and root apical meristem.When the expression level of EIP9 was decreased,the expression level of WUS and CLV3 protein was also reduced.The EMSA assay,further demonstrated that EIP9 protein interacts with WUS protein as a complex which further binds to WUS promoter as a transcription complex.These results suggest that EIP9 protein plays an important role in regulating stem cell maintenance and differentiation in SAM,which provide a new pathway to explore the mechanism of stem cell maintainance.